how can I access ~/Library/Containers/net.namedfork.DesktopGoose/Data/Library/Application Support/Desktop Goose/Memes/
and like create my own memes or add new ones??
Just in case you still need help with this, the ~ folder refers to the location where you installed the goose too. So go there, then browse through to that directory tree. Drop images in that folder, and the goose should be able to retrieve them.